Formations and emissions of CO/NO2/NOx in the laminar premixed biogas-hydrogen flame undergoing the flame-wall interaction: Effects of the variable CO2 proportion

•Effects of CO2 proportion and FWI on formations of CO/NOx were studied.•The experimental measurements and numerical methods were both employed.•The CO2 content increases EICO of biogas-H2 flame but the strong FWI reduces it.•The CO2 improves prompt and NNH route but suppresses thermal and N2O route.•The CO2 content improve the NO2 conversion but the intensive FWI suppresses it.